Hot ground.

[Richard Moore]

This has been bugging me a bit since Monday. New townhouse. Besides the gas fireplace switches being left buried behind the drywall, I had a single duplex receptacle in the middle of a living room wall that showed Hot/Ground reversed on my 3-light tester. I then used a multi-meter and found that both the ground and the hot gave me 120 volts to the neutral. Because of the hot ground, I didn't feel like taking the cover plate off and just reported it as in need of prompt repair.

However, how would that happen??? None of the other receptacles had any issues so it couldn't simply be the grounding wire in contact with the hot terminal (which, in any case, should have tripped the breaker). I'm left with a horribly bad (even evil) receptacle itself, or some wing-nut who wing-nutted the ground wire pigtail with the hots. Any other options?

Just curious in Seattle.

[Kyle Kubs]

I'd say those two things are your most probable choices but in thinking about it, what did you get between the hot & the ground?

[Richard Moore]

Nothing, although frankly, I didn't spend much time with that one and it's always possible I didn't have contact in the gounding hole. I assume you are thinking multi-wire circuits? Possible, but it would still take some pretty screwy wiring.

[Jim Katen]

This has been bugging me a bit since Monday. New townhouse. Besides the gas fireplace switches being left buried behind the drywall, I had a single duplex receptacle in the middle of a living room wall that showed Hot/Ground reversed on my 3-light tester. I then used a multi-meter and found that both the ground and the hot gave me 120 volts to the neutral. Because of the hot ground, I didn't feel like taking the cover plate off and just reported it as in need of prompt repair.

However, how would that happen??? . . .

Wouldn't reversed polarity explain it? If so, what you thought was the neutral was really hot.

A quick & dirty way to figure these out is to use one of those really cheap neon testers, such as a Detect-o-lite. Stick one probe into a receptacle slot and hold tightly on to the other probe with your fingers. It will glow faintly when you touch it to a hot conductor. DO NOT TRY THIS WITH A MULTIMETER OR WIGGY.

- Jim Katen, Oregon

[Richard Moore]

Wouldn't reversed polarity explain it? If so, what you thought was the neutral was really hot.

Hi Jim,

I've used this same tester many times and it has a different light pattern for reverse polarity (hot/neutral reversed). I think they all do. I've seen that many times. This is the first time I can remember ever seeing the hot/ground reversed pattern. Here, I even took a photo...

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So...yes, you are right that reversed polarity would give me the same readings I got with the multi-tester. But then why would the three-light tester read hot/ground reversed in the first place and not just the normal reversed polarity? I know these things can't diagnose multiple problems but I would expect the same readings for the same condition. BTW...I didn't want to fry my Suretest so I didn't try that. Damn...now you got me wishing I had thrown the breaker, taken the cover off and done a bit more 'vestigating.

Oh well. I stuck a large piece a large piece of tape over the receptacle with "hot ground" written on it. Something is wrong. The builder's electrician can sort it out.

[dnoel]

The actual ground is probably not connected but something is shorting the receptacles 'ground'. Is this plug connected to a switch ?

[hmiller]

My guess would be a loose neutral wire... It is not likely that the ground is really hot. Rather what happens is that your tester is being tricked...

Notice that the "open ground" light uses the far left light only. And the "Hot/ ground reverse" uses left and right lamps.

My guess is the neutral has a poor connection but is not fully disconnected, energizing the far right lamp on the tester.

[Billy_Bob]

For new construction, they will sometimes hire new people without any experience "working under the supervision of an electrician".

And these people will just run wires and connect switches/outlets. The electrician wires the main electric panel.

Many of these people want to go on to become electricians, but a few don't know what they are doing and will not last long.

So no telling how it could have been wired!

They are supposed to check every outlet and switch when they are done. But I have seen them have the beginners do this. Might want to have the appropriate person point this out to whoever did the electrical work. They should have caught it.

[Jim Katen]

Wouldn't reversed polarity explain it? If so, what you thought was the neutral was really hot.

Hi Jim,

I've used this same tester many times and it has a different light pattern for reverse polarity (hot/neutral reversed). I think they all do. I've seen that many times. This is the first time I can remember ever seeing the hot/ground reversed pattern. Here, I even took a photo...

Click to Enlarge

14.61 KB

So...yes, you are right that reversed polarity would give me the same readings I got with the multi-tester. But then why would the three-light tester read hot/ground reversed in the first place and not just the normal reversed polarity? I know these things can't diagnose multiple problems but I would expect the same readings for the same condition. BTW...I didn't want to fry my Suretest so I didn't try that. Damn...now you got me wishing I had thrown the breaker, taken the cover off and done a bit more 'vestigating.

Oh well. I stuck a large piece a large piece of tape over the receptacle with "hot ground" written on it. Something is wrong. The builder's electrician can sort it out.

I just experimented with a piece of lampcord with two bare ends and my pocket three-light tester.

You'll get the two outside lights to light up if you connect the same hot wire to both the neutral and hot screws on the receptacle.

- Jim Katen, Oregon

[Richard Moore]

You'll get the two outside lights to light up if you connect the same hot wire to both the neutral and hot screws on the receptacle.

But, I had 120v between hot and neutral. Thanks for trying though, Jim. I've moved on, but will pick up one of those cheap neon testers for future use in the test you described earlier. I'll sue you if it zaps me! []

[Brandon Whitmore]

But, I had 120v between hot and neutral. Thanks for trying though, Jim. I've moved on, but will pick up one of those cheap neon testers for future use in the test you described earlier. I'll sue you if it zaps me!

I'm still trying to wrap my pea brain around this. Say the ungrounded conductor shorts to the grounded conductor. The grounded conductor is attached to the neutral terminal bar, so power can return to that bar. You won't get a 240 v. reading, because you've only got power to one leg. Wouldn't current travel back on the neutral and give that reading?

[Kyle Kubs]

But, I had 120v between hot and neutral. Thanks for trying though, Jim. I've moved on, but will pick up one of those cheap neon testers for future use in the test you described earlier. I'll sue you if it zaps me!

I'm still trying to wrap my pea brain around this. Say the ungrounded conductor shorts to the grounded conductor. The grounded conductor is attached to the neutral terminal bar, so power can return to that bar. You won't get a 240 v. reading, because you've only got power to one leg. Wouldn't current travel back on the neutral and give that reading?

You've just explained a normally functioning circuit..

I think what dnoel said has merit. It would explain how there is current on the ground but the breaker doesn't trip. Probably one of those really fine quality $0.59 receptacles with a crack in just the right place.

I do my run through the rooms checking outlets and such last, sometimes this is the problem with that lineup, you run into something like this and you want to pull the cover and check it out but, it's always one where you've been there 4 1/2 freagin hours already and you just don't care anymore.